The spine is formed by a column of vertebra that extends between the cranium and pelvis and includes three major regions known as the cervical, thoracic and lumbar regions. There are 7 cervical vertebrae, 12 thoracic vertebrae, and 5 lumbar vertebrae. These vertebrae are separated from one another by intervertebral discs that act as shock absorbers and allow the vertebrae to move relative to each other. A series of approximately 9 fused vertebrae extend from the lumbar region and make up the sacral and coccygeal regions of the vertebral column.
The main functions of the spine are to provide skeletal support and protect the spinal cord. If the normal physiology of the spine is disrupted due to trauma, degeneration, or other ailments, the delicate nervous tissue proximate the spine may be affected and the patient may experience symptoms ranging from discomfort to paralysis. In such instances surgical correction is often performed to relieve, or at least reduce, the patient's symptoms. Often times the surgical correction involves positioning an implant into the intervertebral space. This generally provides support and restores a more natural height to the disc space. The implants may be designed to provide a scaffold for bone ingrowth between the vertebra (i.e. fusion implant) or the implants may be designed to replace the function of the intervertebral disc (i.e. partial or total disc replacement).